For now, the only alternative to using BlueSky as your ATProto identity provider is to BYOD (Bring Your Own Domain, using did:web).
The fundamental problem with using a domain name as a social identity, is that it's like having to pay every year to keep your passport working. If you can't afford to pay every time your domain name comes up for renewal, you lose the ability to identify yourself on every service where you BYOD.
So only geeks who have domains anyway will do it.
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